The construction, acquisition, improvement, equipment, custody, operation, maintenance and administration of all works for the collection, treatment or disposal of sewage within the city and in the sanitary district which shall be acquired, constructed, operated or maintained by the Sanitary Board, and the employment of all engineers, architects, inspectors, superintendents, collectors, attorneys and other employees in the judgment of the Board, necessary to the execution of its powers and duties and the collection of all revenues from the works acquired, constructed, operated or maintained by it, shall be under the supervision and control of the Sanitary Board.
('71 Code, § 147.05)